Electric arc process for making hydrogen cyanide, acetylene and acrylonitrile

ABSTRACT

A lower hydrocarbon having from one to eight carbon atoms is passed through an electric arc, heated therein above about 1,000* F., and immediately mixed with nitrogen or a nitrogencontaining compound, which mixture immediately reacts to form acetylene, hydrogen cyanide and other products, which products are quenched below about 1,000* F. If desired, the resulting products are further reacted to form acrylonitrile from the further reaction of the acetylene with the hydrogen cyanide present. By not passing the nitrogen-containing compound through the arc during the process, severe errosion of the electrodes is avoided. By passing only the lower hydrocarbon through the arc during the process, it is not necessary to employ any inert arc gas, which would increase the cost of operation and the difficulty of separation of products. Because of lower cost and availability, methane and ammonia are preferred as the two reactants. Nitrogen and other nitrogen-containing compounds are disclosed as suitable nitrogen sources to replace the ammonia. Apparatus features are the combination of a rotating arc heater with a fluidized bed arc effluent quench and feed preheater and, if desired, fluidized bed acrylonitrile from hydrogen and acetylene reactor followed, if desired, by a suitable series of fractionators.

ite tates atet Bjornson et al.

[ 1 July 4, 1972 [541 ELECTRIC ARC PROCESS FOR MAKING HYDROGEN CYANIDE,ACETYLENE AND ACRYLONITRILE [72] lnventors: Gelr Bjornson; Homer M. Fox,both of Bartlesville, Okla.

[73] Assignee: Philips Petroleum Company [22] Filed: Feb. 24, 1969 [21]Appl. No.: 801,364

[52] U.S. Cl ..204/l71, 204/323 [51] Int. Cl. ....B01k 1/00, C22d 7/08[58] Field of Search ..204/17l, 178, 323-328 [56] References CitedUNITED STATES PATENTS 3,168,592 2/1965 Cichelli et al ..204/171 X3,460,902 8/1969 l-lirayarna et al ..204/171 Primary Examiner-John H.Mack Assistant Examiner-Neil A. Kaplan Att0meyYoung and Quigg lOl D 57ABSTRACT A lower hydrocarbon having from one to eight carbon atoms ispassed through an electric arc, heated therein above about l,000 F., andimmediately mixed with nitrogen or a nitrogencontaining compound, whichmixture immediately reacts to form acetylene, hydrogen cyanide and otherproducts, which products are quenched below about l,000 F. If desired,the resulting products are further reacted to form acrylonitrile fromthe further reaction of the acetylene with the hydrogen cyanide present.By not passing the nitrogen-containing compound through the arc duringthe process, severe errosion of the electrodes is avoided. By passingonly the lower hydrocarbon through the arc during the process, it is notnecessary to employ any inert arc gas, which would increase the cost ofoperation and the difficulty of separation of products. Because of lowercost and availability, methane and ammonia are preferred as the tworeactants. Nitrogen and other nitrogencontaining compounds are disclosedas suitable nitrogen sources to replace the ammonia.

Apparatus features are the combination of a rotating arc heater with afluidized bed are effluent quench and feed preheater and, if desired,fluidized bed acrylonitrile from hydrogen and acetylene reactorfollowed, if desired, by a suitable series of fractionators.

6 Claims, 2 Drawing Figures CH4 I06 [EFFLUENT PA'TENTEDJUL 4 I972 SHEET2 OF 2 INVENTORS G. BJORNSON BY H. M. FOX

E ATTORNEY;

ELECTRIC ARC PROCESS FOR MAKING HYDROGEN CYANIDE, ACETYLENE ANDACRYLONITRILE This invention relates to an electric arc process andapparatus for making hydrogen cyanide, acetylene and acrylonitrile fromthe reaction of C to C hydrocarbons, preferably methane, with nitrogenor nitrogen-containing compounds, preferably ammonia, characterized bythe fact that none of the nitrogen or nitrogen-containing compoundspasses through the arc during the process, and that only thehydrocarbons pass through the arc during the process without any inertarc gas, such as hydrogen, argon, nitrogen or mixtures thereof, Theinvention is further characterized in that it can simultaneously producesubstantial quantities of both acetylene and hydrogen cyanide in asingle stream, which stream is suitable for direct conversion toacrylonitrile.

In the prior art, as shown in US. Pats. to Perry, No. 2,682,447 andHammer, No. 3,213,260, it was old to pass all the reactants through theelectrical arc, which practice is found to be destructive to theelectrodes, causing them to erode rapidly. It was also old to pass onlyan inert arc gas through the electrical arc, as shown in Case US. Pat.No. 3,114,691 or Begley et al. US. Pat. No. 3,419,597, with resultingcomplications and increased cost in operation and in separation of theproducts and the arc gas, and recycle of the arc gas.

The present invention unexpectedly demonstrates that by passing only thehydrocarbon through the electrical arc and immediately mixing in thenitrogen or nitrogen-containing reactant, the difficulties of the priorart as to erosion of electrodes or difficult separation of the inert arcgases are both avoided, and the process and apparatus operate to givegood yields of the desired products.

The present invention employs several novel combinations andsubcombinations of apparatus in carrying out the process. Thecombinations of a rotating arc heater somewhat similar to Hammer U.S.Pat. No. 3,213,260, with a fluidized bed quench and feed heater somewhatsimilar to 2 of Rex US. Pat. No. 2,902,437, followed if desired by afluidized bed reactor somewhat similar to l of Rex, cited, followed ifdesired by a series of fractionators somewhat similar to those in PerryU.S. Pat. No. 2,682,447 are all regarded as patentable improvements in acombined apparatus for making hydrogen cyanide, acetylene andacrylonitrile.

One object of the present invention is to provide a novel process ofmaking hydrogen cyanide, acetylene and acrylonitrile.

Another object is to provide such processes which avoid excessiveelectrode erosion.

Another object is to provide such processes which avoid the use of aninert arc gas.

Another object is to provide apparatus for carrying out theabove-described processes of each of the preceding objects.

Numerous other objects and advantages will be apparent to those skilledin the art upon reading the accompanying specification, claims anddrawings.

In the drawings:

FIG. 1 is a flow diagram of the process of this invention, showing theapparatus in schematic form.

FIG. 2 is an elevational view of the arc heater of FIG. 1, with theupper portion in cross section at its diameter to show the features ofconstruction of the arc heater as actually used in obtaining the data ofthe examples.

FIG. 3 is a view similar to FIG. 1 of a second form of arc heateremploying three-phase alternating current, which may be used in thepractice of the present invention.

The utility of acetylene, acrylonitrile and hydrogen cyanide is wellknown.

In 1960 in the United States, 770 million pounds of acetylene was usedin the manufacture of vinyl chloride by the reaction of acetylene andhydrogen chloride, in the formation of neoprene, reaction with hydrogencyanide to form acrylonitrile, reaction with chlorine to formtrichloroethylene on dehydrogenation, reaction with carbon monoxide andalcohol or water to form acrylic acid or its esters, and many otheracetylene reaction products useful in polymers, film, sheeting, floorcoverings, textile and paper coatings, paints and adhesives. Acetylenecan be reacted with acetic acid to form vinyl acetate and polyvinylacetate useful for latex paint, adhesives, textile finish and many otheruses.

In 1960 in the United States, 400 million pounds of acrylonitrile wasproduced, mainly to be used in the production of acrylic fibers, rugs,fabrics, modacrylic fibers, nitrile rubber and plastics. Many other usesexist and could be listed.

In 1964 in the United States, 445 million pounds of hydrogen cyanide wasproduced, the chief use being to make acrylonitrile. The next largestuse is in making methyl methacrylate, followed by making adiponitrileand next making sodium cyanide. The remaining hydrogen cyanide is usedin ferrocyanides, acrylates, ethyl lactate, latic acid, chelatingagents, optical laundry bleaches and pharmaceuticals.

Because of the intense heat of the electric are, any hydrocarbon thatwill vaporize completely below 500 F. can be heated if necessary and sovaporized and used as hydrocarbon feed stream 4 in FIG. 1; but becauseof availability, cheapness and because less or no preheat is necessary,methane (CH is preferred. However, C to C hydrocarbons are alsopreferred to a less degree for reasons similar to methane. They may beparaff'mic, olefinic, diolefinic, aromatic, alkyl aromatic or evenacetylenic, although obviously their price places an economicdisadvantage on all but the paraffinic. One may use in this inventionmethane, ethane, propane, butane, pentane, hexane, heptane, octane,ethene, propene, butene, pentene, heptene, octene, ethyne, propyne,butyne, pentyne, hexyne, heptyne, octyne, propadiene, butadiene,pentadiene, hexadiene, heptadiene, octadiene, benzene, toluene andxylene almost equally well except for the relative cost of the feedstockin the practice of this invention. Methane is used in the examples belowbecause of its relative cost, availability and low temperaturevaporization. Obviously, ethyne would be uneconomical as a feedstock tomake acetylene (which is ethyne), but it has utility in making theproduct acrylonitrile.

Because of the intense heat of the electric arc, nitrogen (N hydrazine(H NNH or any nitrogen-containing organic compound that will vaporizecompletely below 500 F. can be heated if necessary and so vaporized andused as a nitrogen-containing feed stream 6 in FIG. 1; but because ofavailability, cheapness and because less or no preheat is necessary,ammonia (NH is preferred. However, other nitrogencontaining materialscan be used; in particular, organic amines can be used, such as, forexample, primary, secondary and tertiary amines or othernitrogen-containing compounds having up to about 12 carbon atoms permolecule. For example, N NI-I H NNH methylamine, triethylamine orpyridine can be used in the practice of this invention almost equallywell except for the relative cost of the feedstock. Ammonia is used inthe examples below because of its relative cost, availability and lowtemperature vaporization. Obviously, it would not be economical to useacrylonitrile as a feedstock to make acrylonitrile, but it will be notedin the drawing that in pipe 7 acetonitrile and in pipe 8 propionitrileand heavier nitriles may be recycled to the arc heater as part of thenitrogen-containing feedstock 6. The heavier nitriles in line 8 mayinclude trans-l-cyanobutene, cyanobutene, 2-cyanobutadiene, 3-cyanopropene, transl-cyanobutene2, cisl -cyanopropene,cis-l-cyanobutene-Z, trans-cyanobutadiene, cis-cyanobutadiene and someothers.

In FIG. 1 the hydrocarbon feedstock 4 is preferably preheated byindirect heat exchange in heating coil 9 in quench chamber 11 with afluidized bed of material having an upper level 12 to its dense phase.From coil 9 the preheated hydrocarbon feedstock goes through line 13preferably to inlets A, B, C and/or D of the arc heater 14, although asmore fully shown in FIG. 2 some of the hydrocarbon feedstock could, ifdesired, go to inlets E, F and G. The nitrogen-containing stream 6 ispreferably similarly preheated in heating coil 16 and passes throughline 17 where it may have recycle products added through line 18 andpreferably passes to inlets E, F and/or G of the arc heater 14, althoughas more fully shown in FIG. 2 it could, if desired, go to inlets A andB, but would never go to inlets C and D except for purposes of providinga comparative run showing the advantages of not running thenitrogen-containing stream through the electric are per se. However, thearc 19 is preferably started by injecting nitrogen through inlets C andD and then when the arc is established simultaneously switching tohydrocarbon feed through C and D and nitrogen-containing feed throughinlets A, B, E, F or G. Starting the are with hydrocarbon feed throughinlets C and D may cause carbon deposits to form in the arc heater, butonce the arc is established this carbon deposit is no longer a problem.

In the present method for the concurrent preparation of substantialquantities of HCN and acetylene by pyrolysis of a lower hydrocarbon suchas methane in line 13 with a nitrogencontaining material such as ammoniain line 17 in a high-performance arc heater generally designated as 14in FIG. 2, preferably utilizing a magnetically-rotating arc 19 betweentwo toroidal electrodes 21 and 22, it has been found that improvedoperation can be obtained by passing only the hydrocarbon into inlets Cand/or D and through the actual region of the are 19 and introducing theammonia at a point A, B, E, F and/or G where it bypasses the intense arcregion. While inlets A and B are operable in the practice of thisinvention, inlets E, F and/or G are preferred for the entry of theammonia, as then it passes by the arc 19 but spaced therefrom bypyrolyzing hydrocarbons from inlets C and/or D. Some hydrocarbons canenter inlets A, B, E, F and Galso, as it is immaterial whether all thehydrocarbons go through arc 19, but none of the nitrogen-containingmaterial should be allowed to pass through are 19, because then it willcause the metal of electrodes 21 and 22 to vaporize and rapidly erode,which obviously is highly undesirable.

The proportions of nitrogen-containing feedstock to hydrocarbonfeedstocks will vary depending upon the feeds used, but will be such toprovide the desired ratio of acetylene to hydrogen cyanide in theeffluent. When the feeds are ammonia and methane, the ammonia feed rateis frequently in the range of 25-40 weight percent of the methane rate.

Arc heater 14 comprises in combination two annular copper electrodes 21and 22 separated by an annular arcestablishing plate 23 spaced from eachelectrode by electrical insulating plates 24, 26 and 27 made of glass,Micarta or other known suitable heat-resistant electrical insulation.Opposite poles of an electrical current generator 28 are connected bywires 29 and 31 to electrodes 21 and 22, respectively; and when 28 is analternating current generator, it is preferred to have an inductivereactor 32 in series in one of the wires to provide an inductive kick toreignite the are on each half of the A. C. voltage wave. Suitablechromium and copper alloys are known which can be used instead of purecopper for electrodes 21 and 22. When 28 is a direct current generator,then inductive reactor 32 preferably is omitted.

Materials which are to pass directly through the are 19 are suppliedthrough inlets C and/or D. In starting up the arc 19, it is preferred touse nitrogen as the gas introduced at C and D before any hydrocarbon orammonia is introduced. Metal starting pins 33 and 35 are pushed intocontact with electrodes 21 and 22, generator 28 is started, and pins 33and 35 are then withdrawn to the position shown, creating two arcs (notshown) from 21 to 23 and from 23 to 22. The gas entering through Cand/or D and the magnetic field created by current from generator 33 inone or both of annular magnetic field coils 34 and 36 move the two arcsuntil they meet in the center of plate 23 and the joined arc 19 thenpulls loose from plate 23 and runs directly from electrode 21 toelectrode 22. The magnetic field of coils 34 and/or 36 rotates the arc19 so it will distribute its erosion of electrodes 21 and 22 evenly. Theoperation of field coils 34 and 36 is similar to that of coils 28 and 30of Hammer US. Pat. No. 3,213,260 patented Oct. 19, 1965, and needs nofurther explanation. It is preferred that the arc rotates at a speedwhich is at least 2,000 ftJsec.

The hydrocarbon feed, for example methane, is then immediately andcompletely substituted for the nitrogen in inlets C and D, and no morenitrogen-containing material passes through arc 19. The nitrogen ornitrogen-containing material, such as ammonia, is then injected into thearc heater through inlets A, B, E, F or G and the mixed effluents emergethrough outlet H into the quench 11 of FIG. 1. The conditions ofoperation will be such that from about 2,800 to about 10,000, preferablyfrom about 6,000 to about 8,000, B.t.u. are absorbed by each pound ofreaction mixture. Short residence times, for example 0.001 to 0.1second, are generally used. Any convenient pressure, includingatmospheric pressure, is suitable.

In FIG. 2, the electrodes 21 and 22 may be protected by annular heatshields 37 and 38 made of any noncorrosive metal, such as brass,stainless steel or the like, preferably separated from electrodes 21 and22 by electrical insulation 39 and 41. lnlets A, B, C, D, E, F, G andoutlet H are also preferably provided with electrically-insulated pipesections so that are 19 is confined to electrodes 21 and 22 and does notlose current by short circuits in the inlet pipes. v

Preferably, all parts 21, 22, 23, 37 and 38 are water cooled. The watercooling spaces 42, 43, 44, 46, 47, 48 and 49 are supplied with water andwater removed as shown by the arrows. Electrical current losses can beavoided by separate water cooling systems for each water-cooled spot.

Feedstock lines 13 and 17 are connected to inlets A, B, C, D, E, F and Gin FIG. 1 by two sets of valves, as by valves 51 and 52 for inlet A.Obviously, by opening and closing selected valves, any feedstock orcombination of feedstocks may be injected at each inlet as desired.

In FIG. 1 the efiluent from the arc heater 14 passes through outlet lineH into the bottom of quench chamber 11 and up through the dense phase ofa fluidized bed 12 in indirect heat exchange with the methane in coil 9and the ammonia in coil 16, thereby quenching the effluent to belowabout l,000 F. and preheating the hydrocarbon and ammonia feedstocks.The quenching can be to about 650 to 1,200 F. if desired. The fluidizedsolid 12 in the heat exchanger can be any conventional particulatesolid, such as charcoal, clay or the like. The fluidized solids pluscarbon black picked up from the effluent H may be drawn off through line53 and blown into regenerator 54 with air 56, which will burn off anyadded carbon black or hydrocarbon as gaseous CO and H 0 which passes outline 57 overhead, the regenerated particulate solids returning to quenchvessel 11 through line 58 controlled by valve 59 controlled by liquidlevel controller 61 to maintain the upper level of the dense phase invessel 11 at 12 as shown.

As common practice in such fluidized bed vessels as 11, the gas abovelevel 12 emerges through exit line 62 tangentially into cycloneseparator 63, from which dust is returned through line 64 to a pointbelow level 12, and dust-free gas passes up line 66 into the reactor 67.Recycled acetylene may be added by line 68 and compressor 69, ifdesired, if valve 71 is opened.

The reactor eflluent in pipe 66, being cooled to about l,000 F. andessentially free of elemental carbon, is conducted to catalytic reactor67. This catalytic reactor 67 contains any conventional catalystsuitable for converting the acetylene and hydrogen cyanide toacrylonitrile. Preferred catalysts are alkali metal cyanides on suitablecatalytic supports, such as charcoal, silica, natural and syntheticaluminosilicates, clays, refractory metal oxides and the like, andmixtures thereof. A particularly preferred catalyst for fluidized bedoperation is one containing from about 15 to about 20 weight percent ofequal parts by weight of sodium cyanide and potassium cyanide supportedon hardwood charcoal which has been pretreated with hot caustic solutionto remove a portion of the ash content, and then with hot oxalic acidsolution. This catalyst is then blended with a fluidization aid whichcan be an inert material, such as silica, sand or the like, butpreferably can be a material such as an attrition ground silica on whichwas deposited equal portions of the mixed sodium and potassium cyanidesand about 2 weight percent calcium oxide. The temperature within thereaction zone is preferably maintained within the range of from about650 F. to about 1,200 E, and the feed rate will have a gaseous hourlyspace velocity in the range of from about 50 to about 3,000 volumes ofgas per volume of catalyst per hour.

Catalyst may be drawn out of reactor 67 through line 72 into regenerator70, which operates the same as regenerator 54 and its correspondingparts 56, 57, 58, 59 and 61. The overhead gas in 67 is removed throughline 73 in the same manner as through parts 62, 63 and 64 of vessel 1 1.

Although fluidized bed operation under these conditions is presentlypreferred, other catalyst systems and processes (not shown) which willcause hydrogen cyanide and acetylene to combine efficiently toacrylonitrile can be used. For example, this conversion can be carriedout in a fixed bed operation within the range of from about 300 F. toabout l,500 F. using a catalyst comprising an oxide of a Group lIB metalof the Periodic Table, preferably zinc oxide or cadmium oxide. Group IIBmetals are zinc, cadmium and mercury.

Catalyst is removed from reactor 67 via pipe 72 for disposal and/orregeneration. The effluent from reactor 67 passes via pipe 73 into aseparations area shown as separation zones 74, 76, 77 and 78. Theeffluent in pipe 73 contains, in addition to the acrylonitrile product,nitrogen-containing by-products, such as up to about parts by weight ofacetonitrile and of propionitrile, and up to about 2 parts of heavynitrogen byproducts including trans-l-cyanobutene, cyanobutene, 2-cyanobutadiene, 3-cyanopropene, trans-l-cyanobutene-2,cisl-cyanopropene, cisl -cyanobutene-2-, trans-cyanobutadiene,cis-cyanobutadiene, and some other heavier materials.

The effluent contained in pipe 73 is first passed into separation zone74 from which the hydrogen, methane, nitrogen and other light materialsare removed in an overhead stream 79. The remainder 81 of the stream ispassed into separation zone 76 from which any acetylene present isremoved as an overhead 82 and recycled to catalytic reactor 67 by meansof pipe 68, or can be drawn off through valve 83 and line 84. Theremainder 86 of the product-containing stream is conducted to separationzone 77 from which propionitrile and other heavier nitrogen-containingby-products are removed as an underflow through pipe 8 while an overheadstream containing acetonitrile and acrylonitrile is passed through pipe87 to separation zone 78 for the separation of acrylonitrile productoverhead through pipe 88 and for the removal of acetonitrile as anunderflow through pipe 7. Because acrylonitrile and acetonitrile areclosely boiling materials, an effective fractional distillation columnmust be used for this last separation. The acetonitrile and thepropionitrile and other heavier nitrogen-containing by-products areadvantageously recycled to the arc heater through pipe 18 containingcompressors 89 and 91.

Other catalyst systems can result in varying amounts of other impuritiesor by-products. Appropriate modifications, within the skill of theseparation art, can be made in the present separation sequence to carryout any required recycles and product removals.

FIG. 3 is a schematic view of how a three-phase A. C. are can be used.Three-phase A. C. generator 92 sends separate phase currents throughwires 93, 94 and 96 and inductive reactors 97, 98 and 99 to electrodes101, 102 and 103 separated by electrical insulators 104 and 106. Methaneand ammonia are added and efiluent removed as shown. Generator 33 andcoils 34 and 36 rotate the three arcs.

The invention can be further illustrated by the following examples:

EXAMPLE I A number of runs where methane and ammonia were converted toacetylene and hydrogen cyanide were carried out using a 1,500 kw. archeater (Westinghouse Marc 30) of the general type shown schematically inFIG. 2. A ii-inch gap between the toroidal electrodes was used in theseruns and only the upstream field coil 34 was utilized to rotate the arc.

The methane portion of the feed was introduced into the arc heater inthe following manner: 5.5 percent through port A, 5.5 percent throughport B, 44.5 percent through port C and 44.5 percent through port D.Thus, the bulk of the methane (89 percent) was fed into the heater atupstream ports, that is, at locations where it is passed through therapidly-rotating arc.

The ammonia portion of the feed, on the other hand, was introduced intothe arc heater at downstream ports, that is, at iocations where theammonia did not pass through the actual are. To by-pass the arc, theammonia feed stream was divided evenly and introduced into downstreamports E and F.

The effluent from the arc heater was sampled and analyzed. The resultsof these analyses and other essential conditions of the runs are shownin Table I.

EXAMPLE II The criticality of the mode of ammonia introduction isillustrated by the results of the three runs in which the ammonia wasintroduced not according to the process of the invention but at a pointupstream of the arc. These runs were made with the same arc heater ofExample I and under the same essential conditions except that theammonia was added through upstream port D. The methane feed was splitinto several portions and introduced as follows: 8.3 percent into portA, 8.3 percent into port B, 66.8 percent into port C, 8.3 percent intoport E and 8.3 percent into port F. Thus, 83.4 percent of the methaneand all of the ammonia were introduced into the arc heater so as to passdirectly through the intense region of the arc.

In one run lasting about 5 minutes, methane at 332.2 lb./hr. and ammoniaat 31.0lb./hr. were fed into the heater operating at a gross A. C. powerlevel of 890 kw., resulting in a net enthalpy of 5,593 B.t.u./lb.methane plus ammonia feed. Analysis of the effluent showed methaneconversion at 78.2 percent and ammonia conversion at percent, but thereactor effluent showed a green color indicating electrodedeterioration.

In another subsequent run in the same apparatus, methane at 414.0lb./hr. and ammonia at 44.1 lb./hr. were fed into the heater operatingat a gross A. C. power level of 680 kw. resulting in a net enthalpy of3,608 B.t.u./lb. methane plus ammonia feed. Analysis of the effluentshowed 40 percent methane conversion and 92 percent ammonia conversion.However, the test was terminated after about 2 minutes due to failure ofthe copper electrodes.

In still another test in essentially the same apparatus, methane at 359lb./hr. and ammonia at about 60 lb./hr. were fed into the arc heater ata gross A. C. power level of 634 kw. However, after operating at about 4minutes, the effluent showed green and the electrodes failed, oneelectrode being ruptured.

These data, considered in relation to the examples of the previousExample I utilizing the invention process, indicate that the point atwhich the ammonia is fed into the arc heater is critical to thesuccessful operation of the process. In each of the preceding inventionruns of Example I, no electrode wear had been observed.

EXAMPLE III In the arc heater described in Example I, methane isintroduced at the same ports with the same distribution, but at a rateof about 500 lb./hr. Ammonia is also introduced as in Example but atabout lb./hr. About 1,750 kw. of gross power is applied to the archeater, resulting in a net enthalpy of about 6,530 B.t.u./lb. methaneplus ammonia.

Analysis of the effluent shows that an essentially equimolar amount ofacetylene and hydrogen cyanide are produced at rates of about 200 lbJhr.each. Such a stream is cooled, filtered, and contacted with a charcoalcatalyst promoter with about 10 weight percent KCN and about 10 weightpercent NaCN in a fluidized bed reactor operating at about 950 F. toproduce acrylonitrile. Nitrogen-containing products other thanacrylonitrile are recycled to the arc heater being in- 2. The process ofclaim 1 in which the mixed stream containing acetylene and hydrogencyanide is passed through a catalytic reaction zone containing acatalyst suitable for converting the acetylene and hydrogen cyanide toacrylonitrile troduced through the same feed ports as the ammonia feed 5and thereby pr duc ng ac ylonitrile h r fr mstream. 3. The process ofclaim 1 in which the hydrocarbon is TABLE I Ammonia Mothano converted toconverted Ammonia (lross Not to llow AL. onthal y Methane llydrogenAmmonia hydrogen Methanoflow rate ratn power B'IU/ 1). conversionAcetylene cyanide conversion cyunidv (lb./hr.) (In/hr.) (kw CII4+NH3(percent) (percent) (percent) (percent) (percent) Having described ourinvention, we claim: methane and the nitrogen-containing compound isammonia. 1. A process for the formation of acetylene and hydrogen 4. Theprocess of claim 2 in which the hydrocarbon is cyanide comprising thesteps of passing a lower C to C methane and the nitrogen-containingcompound is ammonia. h d b i a fi Stream h h an electric arc and 5. Theprocess of claim 2 in which the catalytic reaction h b h i id fir tstream above about ogo zone comprises a fluidized bed of a catalystconsisting of alkali mediately mixing this first stream with a secondstream of a metal Y PP on catallflc PP selected frofnnitrogen-containing compound selected from the group con the groupConslstmg of charcoal, 5111c?! natlflfal and Synthetic sisting ofnitrogen, ammonia, hydrazine and nitrogen-containalummoslllcates, Clays,refractory metal oxldes and mlxtu'l'es ing organic compounds having fromone to 12 carbon atoms per molecule, which second stream has not passedthrough said arc, and quenching the mixed streams to below about 1,000F. to thereby produce acetylene and hydrogen cyanide in said mixedstreams.

thereof.

6. The process of claim 2 in which the catalytic reaction zone comprisesa fixed bed containing an oxide of a Group IIB metal of the PeriodicTable.

2. The process of claim 1 in which the mixed stream containing acetyleneand hydrogen cyanide is passed through a catalytic reaction zonecontaining a catalyst suitable for converting the acetylene and hydrogencyanide to acrylonitrile and thereby producing acrylonitrile therefrom.3. The process of claim 1 in which the hydrocarbon is methane and thenitrogen-containing compound is ammonia.
 4. The process of claim 2 inwhich the hydrocarbon is methane and the nitrogen-containing compound isammonia.
 5. The process of claim 2 in which the catalytic reaction zonecomprises a fluidized bed of a catalyst consisting of alkali metalcyanides supported on catalytic supports selected from the groupconsisting of charcoal, silica, natural and synthetic aluminosilicates,clays, refractory metal oxides and mixtures thereof.
 6. The process ofclaim 2 in which the catalytic reaction zone comprises a fixed bedcontaining an oxide of a Group IIB metal of the Periodic Table.